Optical information recording medium, an optical information recording apparatus, an information processing apparatus, program and information recording method

ABSTRACT

An optical information recording apparatus can maintain a stable recording quality when recording information on an optical information recording medium having a recording layer of a multilayer structure. An optical information recording medium of a rotating type has a plurality of recording layers each having an information recording area in which information is recorded using a laser beam. An inner power calibration area is provided in each of the recording layers at a location closer to a center of rotation of the optical information recording medium than the information recording area, and is used to perform a test write in an optimum power control process to acquire an optimum recording power of the laser beam. The outer power calibration area is provided at a location farther from the center of rotation than the information recording area, and is used to perform a test write in an optimum power control process to acquire an optimum recording power of the laser beam.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a U.S. continuation application filed under 35U.S.C. 111(a) claiming benefit under 35 U.S.C. 120 and 365(c) of PCTapplication JP2004/003938, filed Mar. 23, 2004.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention generally relates to information recordingtechniques and, more particularly, to an optical information recordingtechnique for recording information on an optical information recordingmedium having a multi-layer recording layer that contains an informationrecording area.

2. Description of the Related Art

In recent years, with improvement in their functions, personal computers(hereinafter, may be abbreviated as PCs) have become capable of handlingaudio-visual (AV) information such as music information or imageinformation. Since an amount of the AV information is extremely large,optical discs such as CD (Compact Disc) or DVD (Digital Versatile Disc)have attracted attention as an optical information recording medium.Then, a price-reduction of the optical discs such as CD or DVD hasprogressed, which results in that an optical disc drive unit as anoptical information recording apparatus has become popular as one ofperipheral devices of personal computers.

As a recording/reproducing method applicable to such an optical disc,there are known a constant linear velocity (CLV) method, a constantangular velocity (CAV) method and a zone CLV (ZCLV) method that combinesthe CLV method and the CAV method. According to the CLV method, anoptical disc is rotated at a constant linear velocity, which giveslittle complexity to data management or rotation speed control since arotation speed is constant and a linear velocity is increased as it goesto an outer side, but is capable of providing a large recordingcapacity. On the other hand, according to the CLV method, it isnecessary to increase a rotation speed of an optical disc as a recordingpoint goes inner side of the optical disc, which makes it difficult torotate the optical disc at such a high speed. Moreover, an increase inthe rotation speed of the optical disc may cause a problem of increasingmotor cost, increasing sound and vibration or difficulty in servo systemdesign.

In this regard, the CAV method rotates an optical disc at a constantangular velocity (rotation speed), which makes easy to manage data orcontrol the rotation speed. However, a recording capacity achieved bythe CAV method is smaller than that of the CLV method. Additionally,according to the ZCLV method, an optical disc is divided into aplurality of zones in a radial direction so that a linear velocity isconstant within each zone. Then, a rotation speed is varied so that thelinear velocity is increased as it goes to outer side of the opticaldisc. Therefore, the ZCLV method has the advantages of both the CLVmethod and the CAV method.

However, even if a recoding is performed according to the ZCLV method,when attempting a higher recording speed, there is a limitation in anoutput power of a semiconductor laser as a light source used in anoptical disc drive unit. For this reason, for example, there may be acase in which a recording power necessary for achieving a desiredrecording characteristic exceeds a maximum output power of asemiconductor laser when an insensitive optical disc is used.

Thus, usually, an optical disk drive unit performs a test write on anoptical disc to record before starting recording on the optical disc.Then, the optical disk drive unit acquires an optimum recording powerbased on a reproduction signal characteristic obtained by reproducinginformation recording in a area where the test write was performed so asto perform the recording with the thus-obtained optimum recording power.Thereby, a good recording quality can be achieved. Hereinafter, theacquisition of the optimum recording power based on the reproductionsignal obtained from the area where the test write is performed isreferred to as an optimum power control (OPC). The area where the testwrite is performed when performing the OPC may be referred to as a powercalibration area (PCA).

In recent years, a multi-layer optical disc having a recording layercontaining a plurality of layers instead of single layer has beendeveloped. As such a multilayer optical disc, there is known one whichuses an organic dye material in addition to a reproduction only opticaldisc having multilayered embossed pits. Since the organic dye materialreacts with light irradiation and has transparency (high opticaltransmittance), the organic dye material is suitable for a material ofthe multilayer optical disc.

Japanese Laid-Open Patent Application No. 2003-22532 discloses anoptical disc apparatus for performing recording or reproduction on suchas multilayer optical disc.

In the meantime, there is a problem mentioned below when performing arecording on a multilayer optical disc having a recording layercontaining a plurality of layers. For example, when recordinginformation on a second recording layer of a two-layer disc having tworecording layers on the same recording side, the recording of the secondrecording layer is performed by transmitting a light beam through thefirst recording layer. Therefore, an amount of the light beam reachingthe second recording layer may be changed depending on a state of thefirst recording layer as to whether it is in a erased state (highreflectance, low transmittance) or a recorded state (low reflectance,high transmittance). Accordingly, there is a problem in that an optimumrecording power acquired by OPC is changed due to changes in the amountof the light beam. Such a fluctuation in the optimum recording power maybe a cause of degradation of recording characteristic such as a jitteror an error rate of the second recording layer.

SUMMARY OF THE INVENTION

It is a general object of the present invention to provide an improvedand useful optical information recording apparatus in which theabove-mentioned problems are eliminated.

A more specific object of the present invention is to provide an opticalinformation recording apparatus which can maintain a stable recordingquality when recording information on an optical information recordingmedium having a recording layer of a multilayer structure according to aconstant linear velocity method.

Another object of the present invention is to provide an opticalinformation recording apparatus which can maintain a stable recordingquality when recording information on an optical information recordingmedium having a recording layer of a multilayer structure according to aconstant angular velocity method.

In order to achieve the above-mentioned objects, there is providedaccording one aspect of the present invention an optical informationrecording medium of a rotating type having a plurality of recordinglayers each having an information recording area in which information isrecorded using a laser beam, the optical information recording mediumcomprising: an inner power calibration area provided in each of therecording layers, the inner power calibration area being used to performa test write in an optimum power control process to acquire an optimumrecording power of the laser beam, the inner power calibration arealocated closer to a center of rotation of the optical informationrecording medium than the information recording area; and an outer powercalibration area provided in each of the recording layers, the outerpower calibration area being used to perform a test write in an optimumpower control process to acquire an optimum recording power of the laserbeam, the outer power calibration area located farther from the centerof rotation than the information recording area.

According to the above-mentioned invention, the power calibration areasare provided on each of the inner side and the outer side with respectto the information recording area so that an optimum power calibrationcan be performed on both the inner side and the outer side of therecording layer onto which information is to be recorded, therebyenabling to acquire an optimum recording power corresponding to anintermediate linear velocity between linear velocities of the inner sideand the outer side. Thus, even in a case where the linear velocityincreases toward the outer periphery, an appropriate optimum recordingpower can be obtained.

Additionally, there is provided according to another aspect of thepresent invention an optical information recording apparatus forrecording information on an optical information recording medium of arotating type, which has a plurality of recording layers each having aninformation recording area in which information is recorded using alaser beam, according to a constant linear velocity method, the opticalinformation recording apparatus comprising: optimum power control meansfor acquiring an optimum recording power of the laser beam with respectto the information recording area of each of the recording layers byperforming a test write on a power calibration area provided in each ofthe recording layers; state determination means for determining whetherthe information recording area of a first one of the recording layers isin a recorded state or an erased state, the first one of the recordinglayers being located on a side where the laser beam is incident; andmeans for performing an optimum power calibration process on the powercalibration area of a second one of the recording layers located underthe first one of the recording layers after causing a state of the powercalibration area of the first one of the recording layers to be equal toa state of the information recording area of the first one of therecording layers.

According to the above-mentioned invention, when recording informationon an optical information recording medium having a recording layer of amultilayer structure according to a constant linear velocity, anappropriate optimum recording power can be acquired under a conditionthe same as that when performing information recording operation.

Additionally, there is provided according to another aspect of thepresent invention an optical information recording apparatus forrecording information on an optical information recording medium of arotating type, which has a plurality of recording layers each having aninformation recording area in which information is recorded using alaser beam, according to a constant angular velocity method, the opticalinformation recording apparatus comprising: optimum power control meansfor setting an optimum recording power of the laser beam to a recordingpower corresponding to an intermediate linear velocity that is acquiredby an interpolation method using a recording power determined by atest-write performed on an inner power calibration area and a recordingarea performed on an outer power calibration area, the inner powercalibration area being closer to a center of rotation of the informationrecording medium than the information recording area, the outer powercalibration area being farther from the center of rotation of theinformation recording medium than the information recording area; statedetermination means for determining whether the information recordingarea of a first one of the recording layers is in a recorded state or anerased state, the first one of the recording layers being located on aside where the laser beam is incident; and means for performing anoptimum power calibration process on the inner-and outer powercalibration areas of a second one of the recording layers located underthe first one of the recording layers after causing a state of the innerand outer power calibration areas of the first one of the recordinglayers to be equal to a state of the information recording area of thefirst one of the recording layer.

According to the above-mentioned invention, when recording informationon an optical information recording medium having a recording layer of amultilayer structure, an appropriate optimum recording power can beacquired by acquiring a recording power corresponding to an intermediatelinear velocity that is determined using results of the optimum powercalibration performed on the inner side and the outer side under acondition the same as that when performing information recordingoperation. Thus, even in a case where the linear velocity increasestoward the outer periphery, an appropriate optimum recording power canbe acquired.

Additionally, there is provided according to another aspect of thepresent invention an information processing apparatus for processing aplurality of kinds of information processing, comprising: processingmeans for processing the information processing using informationprovided by a memory apparatus; and one of the optical informationrecording apparatuses mentioned above.

Further, there is provided according to another aspect of the presentinvention an optical information recording method for recordinginformation on an information recording medium of a rotating type, whichhas a plurality of recording layers each having an information recordingarea in which information is recorded using a laser beam, according to aconstant linear velocity method, the optical information recordingmethod comprising the steps of: acquiring an optimum recording power ofthe laser beam with respect to the information recording area of each ofthe recording layers by performing a test write on a power calibrationarea provided in each of the recording layers; determining whether theinformation recording area of a first one of the recording layers is ina recorded state or an erased state, the first one of the recordinglayers being located on a side where the laser beam is incident; andperforming an optimum power calibration process on the power calibrationarea of a second one of the recording layers located under the first oneof the recording layers after causing a state of the power calibrationarea of the first one of the recording layers to be equal to a state ofthe information recording area of the first one of the recording layers.

According to the above-mentioned invention, when recording informationon an optical information recording medium having a recording layer of amultilayer structure according to a constant linear velocity, anappropriate optimum recording power can be acquired under a conditionthe same as that when performing information recording operation.

Additionally, there is provided according to another aspect of thepresent invention an optical information recording method for recordinginformation on an optical information recording medium of a rotatingtype, which has a plurality of recording layers each having aninformation recording area in which information is recorded using alaser beam, according to a constant angular velocity method, the opticalinformation recording method comprising the steps of: setting an optimumrecording power of the laser beam to a recording power corresponding toan intermediate linear velocity that is acquired by an interpolationmethod using a recording power determined by a test write performed onan inner power calibration area and a recording area performed on anouter power calibration area, the inner power calibration area beingcloser to a center of rotation of the information recording medium thanthe information recording area, the outer power calibration area beingfarther from the center of rotation of the information recording mediumthan the information recording area; determining whether the informationrecording area of a first one of the recording layers is in a recordedstate or an erased state, the first one of the recording layers beinglocated on a side where the laser beam is incident; and performing anoptimum power calibration process on the inner and outer powercalibration areas of a second one of the recording layers located underthe first one of the recording layers after causing a state of the innerand outer power calibration areas of the first one of the recordinglayers to be equal to a state of the information recording area of thefirst one of the recording layer.

According to the above-mentioned invention, when recording informationon an optical information recording medium having a recording layer of amultilayer structure, an appropriate optimum recording power can beacquired by acquiring a recording power corresponding to an intermediatelinear velocity that is determined using results of the optimum powercalibration performed on the inner side and the outer side under acondition the same as that when performing information recordingoperation. Thus, even in a case where the linear velocity increasestoward the outer periphery, an appropriate optimum recording power canbe acquired.

Additionally, there is provided according to another aspect of thepresent invention a computer readable program to be installed in acomputer of an information recording apparatus for recording informationon an optical information recording medium of a rotating type, which hasa plurality of recording layers each having an information recordingarea in which information is recorded using a laser beam, the programcausing the computer to perform one of the above-mentioned opticalinformation recording method.

Further, there is provided according to another aspect of the presentinvention a processor readable medium storing the above-mentionedprogram to be installed in a computer of an optical informationrecording apparatus for recording information on an optical informationrecording medium of a rotating type, which has a plurality of recordinglayers each having an information recording area in which information isrecorded using a laser beam.

Other objects, features and advantages of the present invention willbecome more apparent from the following detailed description when readin conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an illustration showing an area structure of an optical discaccording to a first embodiment of the present invention;

FIG. 2 is a block diagram of an optical disc drive unit according to thefirst embodiment of the present invention;

FIG. 3 is an illustration for explaining changes in a sate of areproduction signal due to changes in a recording power;

FIG. 4 is a graph showing a relationship between a recording power andan evaluation measurement value;

FIG. 5 is a flowchart of an OPC process;

FIG. 6 is a flowchart of an OPC process according to a second embodimentof the present invention; and

FIG. 7 is a perspective view of a personal computer according to a thirdembodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A description will now be given, with reference to FIG. 1 through FIG.5, of a first embodiment of the present invention.

An optical information recording apparatus according to the firstembodiment of the present invention records information on an opticaldisc, which is a multilayer optical disc having two record layers as arecordable rotation-type optical information recording medium.

FIG. 1 is an illustration showing an area structure of an optical disc100 according to the first embodiment of the present invention. As shownin FIG. 1, the optical disc 100 has a two-layer structure, whichcomprises a recording layer (first layer) 101 located on a side of anoptical pickup 5 (refer to FIG. 2) mentioned later and a recording layer(second layer) 102. The optical disc 100 is a dye-type medium which usesan organic color dye material. FIG. 1 shows a cross-sectional view ofthe optical disc 100 taken along a radial direction. The optical disc100 has an inner PCA 103, an information recording area 104 and an outerPCA 105. The inner PCA 103 is provided an inner side of the informationrecording area 104 so that a test write is performed during an OPCprocess. The outer PCA 105 is provided an outer side of the informationrecording area 104 so that a test write is performed during an OPCprocess. That is, the optical disc 100 according to the presentembodiment has PCAs, which permit a test write during an OPC, on aninner side closer to a center of rotation than the information recordingarea 104 and an outer side farther from the center of rotation than theinformation recording area 104 in a two-layer structure.

FIG. 2 is a block diagram showing a structure of an optical disc driveapparatus 1, which records or reproduces information on or from theoptical disc 100. As shown in FIG. 2, the optical disc drive apparatus 1rotates the optical disc 100 by the a rotation drive mechanism includinga spindle motor 2. The spindle motor 2 is controlled to rotate at aconstant angular velocity (rotation speed) by a motor driver 3 and aservo part 4 so that a write operation can be performed according to theCAV method or the ZCLV method.

An optical pickup 5 is equipped with a semiconductor laser as a lightsource, an optical system, a focusing actuator, a tracking actuator,light-receiving actuator, a position sensor, etc. so as to project alaser beam onto a recording surface of the optical disc 100. The opticalpickup 5 is movable in a radial direction of the disc) by a seek motor(not shown in the figure). The focusing actuator, the tracking actuatorand the seek motor are controlled by the motor driver 3 and the servopart 4 in accordance with signals acquired from the light-receivingelement and the a position sensor so that a laser spot is located at adesired target position on the optical disc 100.

A power setting part 6 drives a laser driver 7 in accordance with a setrecording power so as to drive the semiconductor laser of the opticalpickup 5. The semiconductor laser of the optical pickup 5 is modulatedbetween the recording power and a space power in accordance with a pulsesignal input to the laser driver 7. Thereby, record marks and partsother than the record marks are formed on the recording layers of theoptical disc 100.

It should be noted that although the pulse width set by the laser driver7 may be fixed, the pulse width is set by the pulse setting part 8 inaccordance with a linear velocity and a disc type in the presentembodiment. The reason for setting the pulse width in accordance with alinear velocity and a disc type is to absorb a difference in sensitivityof a record mark length due to variation in the linear velocity and disctype. A disc type can be detected from a reproduction signal generatedwhen information recorded in a specific area of the optical disc by theoptical pickup 5. If, for example, disc manufacturers can bediscriminated according to a certain method, the disc type may beclassified according to each manufacture. It is better if theclassification can be made further in detail within the samemanufacture's discs. More specifically, a specific manufacturerdiscrimination cord (vender cord) may be embedded in the optical disc100 beforehand. Furthermore, a code for classification in further detailmay be embedded in the optical disc 100. As anther method fordiscriminating disc types, various parameters embedded in the opticaldisc 100 may be used. If, for example, a recommended power or pulsewidth is embedded, such information may be used. Thus, an optimum pulsewidth setting (write strategy) can be achieved in response to variousoptical discs of the same manufacture.

When recording data, upon receipt of data transferred from a host (notshown) through an interface (I/F) 9 such as ATAPI or SCSI, a datagenerating part 10 applies to the data an encoding process or amodulating process in a predetermined format, and outputs the data asrecording data in a serial format to the laser driver 7 through thepulse setting part 8.

The optical disc drive apparatus 1 is equipped with a controller 11 forcontrolling each of the above-mentioned parts and also performing eachfunction mentioned later. The controller 11 includes a microcomputercomprising a central processing unit (CPU) which controls each part, aread only memory (ROM) for storing fixed data such as a program executedby the CPU, a random access memory (RAM) for rewritably writing variabledata such as work data, etc. A non-volatile memory 12 is connected tothe controller 11.

Except for a case where an OPC result at the time of recording on theoptical disc 100 recorded in the past is already stored in thenon-volatile memory 12, the controller 11 of the optical disk driveapparatus 1 according to the present embodiment performs an OPC processin the PCA of the optical disc 100 so as to acquire an optimum recordingpower. The OPC means acquisition of an optimum recording power based ona reproduction signal from an area where a test write was performed.During execution of the OPC process, in the inner PCA 103 and the outerPCA 105, a test write for a predetermined number of blocks (for example,10 blocks) corresponding to a predetermined number of times is performedwhile increasing the recording power of the semiconductor laser on anindividual block basis (each step).

When performing the OPC process, data in the test-written area isreproduced so as to acquire a reproduction signal RF, and an evaluationmeasurement value β is obtained from the reproduction signal RF. Thevalue β corresponding to a symmetry of an amplitude when thereproduction signal RF is AC-coupled. That is, referring to if FIG. 3showing a state of the reproduction signal RF according to a recordingpower, (a) indicates an appropriate power, (b) indicates an excessivepower, and (c) indicates an insufficient power. The lower side of thereproduction signal waveform corresponds to a part which forms recordmarks. Since a mark is recorded longer when a power is in excess, theduty shifts to a large even if the duty at a normal time is 50%. If theAC-coupling is performed, the evaluation measurement value β isrepresented as follows, where “a” is an upper side amplitude and “b” isa lower side amplitude that are detected by a peak and bottom detectingcircuit (not shown).β=(a−b)/(a+b)It can be appreciated from the example shown in FIG. 3 that β issubstantially zero if a power is appropriate, β is increased if a poweris in excess, and β is decreased if a power is insufficient. Thus, inOPC, an optimum recording power is obtained as a recording power atwhich the value of β is a target value βtarget (for example, 0.04).

It should be noted that during execution of the OPC process, the opticaldisc 100 is rotated at a constant angular velocity (rotation speed), andthe test write is performed according to the CAV method or the ZCLVmethod. The optimum recording power is calculated according to theabove-mentioned method, an instruction of the recording power issupplied to the laser driver 7.

Here, a relationship between a recording power and the evaluationmeasurement value beta is shown in FIG. 4. FIG. 4 shows an example wherea recording is performed while varying the power with 10 steps. A rangeof variation of the recording power is referred to as an OPC, and acentral power of the range is represented by Pdef. The OPC range may bedefined by varying within a range from +40% to −30% with respect to thePdef with 10 steps, or may be varied with respect to the Pdef within arange from +5 mW to −4 mW by 1 mW.

A β-curve (quadratic) is approximated in accordance with thethus-obtained 10 β values so as to acquire a power Popc corresponding tothe target value βtarget. It is better to obtain the Popc near the Pdefunder a normal condition since the Popc may somewhat fluctuate due to acondition at the time of executing the OPC process, such as a change intemperature. Moreover, since the Popc differs from an optical disc to anoptical disc in many cases, the Popc may be set together with a pulsewidth (write strategy) corresponding to a type of an optical disc.

A description will now be given, with reference to FIG. 5, of an OPCprocess in the above-mentioned controller 11. As shown in FIG. 5, beforerecording information on the optical disc 100, first, a recording stateof the information recording area 104 of the recording layer (firstlayer) 101 of the optical disc 100 is checked using managementinformation of the optical disc 100 (step S1). If the reproductionsignal RF is used, the optical pickup 5 is moved to in a radialdirection from inner side to an outer side so as to acquire thereproduction signal RF. Then, position information of the optical pickup5 and information regarding presence of the reproduction signal RF arestored. When using the management information of the optical disc 100,data in the management information recording area (not shown) isreproduced, and it is checked to what extent the information isrecorded.

After checking the recorded state of the information record area 104 ofthe recording layer (first layer) 101 of the optical disc 100 asmentioned above, an OPC is performed so as to acquire an optimumrecording power. If information is recorded on the information recordarea 104 of the recording layer (first layer) 101 of the optical disc100, (Y of step S2: state determination means), an OPC is performed onthe inner PCA 103 of the recording layer (first layer) 101 of theoptical disc 100 (step S3: OPC means). Thereafter, an OPC is performedon the inner PCA 103 of the recording layer (second layer) 102 of theoptical disc 100 (step S4: OPC means). Subsequently, an OPC is performedon the outer PCA 105 of the recording layer (first layer) 101 of theoptical disc 100 (step S5: OPC means), and, thereafter, an OPC isperformed on the outer PCA 105 of the recording layer (second layer) 102of the optical disc 100 (step S6: OPC means).

On the other hand, if information is not recorded on the informationrecording area 104 of the recording layer (first layer) 101 of theoptical disc 100 (N of step S2: state determination means), an OPC isperformed on the inner PCA 103 of the recording layer (second layer) 102of the optical disc 100 (step S7: OPC means). Thereafter, an OPC isperformed on the inner PCA 103 of the recording layer (first layer) 101of the optical disc 100 (step S8: OPC means). Subsequently, an OPC isperformed on the outer PCA 105 of the recording layer (second layer) 102of the optical disc 100 (step S9: OPC means), and, thereafter, an OPC isperformed on the outer PCA 105 of the recording layer (first layer) 101of the optical disc 100 (step S10: OPC means).

The reason for performing an OPC to the inner PCA 103 and the outer PCA105 of the optical disc 100, respectively, is as follows. As mentionedabove, when performing an OPC, the optical disc 100 is rotated at aconstant angular velocity (rotation speed), and a test write isperformed according to the CAV method or the ZCLV method. If a recordingis performed with a constant angular velocity (rotation speed), thelinear velocity is increased as it goes toward an outer side. Anincrease in the linear velocity requires an increase in a recordingpower. Thus, in the present embodiment, an optimum recording power isacquired by performing an OPC on both an inner part and an outer part ofthe information recording area 104 of the optical disc 100.

Additionally, the reason for first performing the OPC on the recordinglayer (first layer) 101 of the optical disc 100, when information isrecorded on the information recording area 104 of the recording layer(first layer) 101 of the optical disc 100, is as follows. That is, ifinformation is recorded on the information recording area 104 of therecording layer (first layer) 101 of the optical disc 100, an OPC isperformed on the PCA (the inner PCA 103 and the outer PCA 105) of therecording layer (second layer) 102 of the optical disc 100 in a statewhere information is written in the PCA (the inner PCA 103 and the outerPCA 105) of the recording layer (first layer) 101 of the optical disc100 since the OPC is first performed on the recording layer (firstlayer) 101 of the optical disc 100. Thus, an optimum recording power isacquired in the same state where information is recorded on theinformation recording area 104 of the recording layer (first layer) 101of the optical disc 100. Similarly, if information is not recorded onthe information recording area 104 of the recording layer (first layer)101 of the optical disc 100, the OPC is first performed on the recordinglayer (second layer) 102 of the optical disc 100 so that an optimumrecording power is acquired in the same state where information is notrecorded on the information recording area 104 of the recording layer(first layer) 101 of the optical disc 100. As mentioned above, anoptimum recording power can be acquired in the same state whereinformation is recorded on the recording area.

After the OPC on the inner PCA 103 and the outer PCA 105 of the opticaldisc 100 is completed as mentioned above, an optimum recording power isacquired by acquiring a recording power at an intermediate linearvelocity according to an interpolation using a result of the OPCperformed on the inner PCA 103 and the outer PCA 105. Then, thethus-acquired optimum recording power is set as the optimum recordingpower for the optical disc 100 (step S11), and informational recordingis started (step S12). That is, the optimum recording power is acquiredby acquiring a recording power at an intermediate linear velocityaccording to an interpolation using the results of the OPC performed onthe inner PCA 103 and the outer PCA 105 under the same condition as theinformation recording operation when performing information recordingaccording to a constant angular velocity method using the optical disc100 having a recording layer of a multilayer structure. Therefore, evenin a case where the linear velocity increases as it moves toward anouter periphery, the optimum recording power can be acquired. Thereby,when performing information recording according to a constant angularvelocity method using an information recording medium having a recordinglayer of a multilayer structure, a stable recording quality can bemaintained.

It should be noted that in a case where information is recorded on apart of the information record area 104 of the recording layer (firstlayer) 101 of the optical disc 100 and if information is to be recordedon information recording area 104 of the recording layer (second layer)102 of the optical disc 100, the optimum recording power, which isacquired when the OPC is performed first on the recording layer (firstlayer) of the optical disc 100 and the optimum recording power, which isacquired when the OPC is performed first on the recording layer (secondlayer) of the optical disc 100, may be stored as parameters in thenon-volatile memory 12 so that the optimum recording power used can beswitched in the middle of the information recording.

A description will now be given, with reference to FIG. 6, of a secondembodiment of the present invention. An optical disc drive apparatusaccording to the second embodiment has basically the same structure asthe optical disc drive apparatus according to the first embodiment.Thus, in the second embodiment, parts that are the same as the firstembodiment are given the same reference numerals, and descriptionsthereof will be omitted. Although the optical disc drive apparatus 1according to the first embodiment uses the CAV method of the ZCAV methodas the recording and reproducing method with respect to the optical disc100, the optical disc drive apparatus 1 according to the secondembodiment uses the CLV method as the recording and reproducing methodwith respect to the optical disc 100.

When the CLV method is used as the recording and reproducing method withrespect to the optical disc 100, the optical disc 100 is rotated at aconstant linear velocity, and a test write is performed according to theCLV method when performing an OPC. In such a case, since the relativevelocity of the optical disc 100 and the laser beam from thesemiconductor laser of the optical pickup 5 is always constant, it isnot necessary to change the record conditions such as a recording powerand a record pulse width over the whole surface of the optical disc ifan optimum condition is once determined. For this reason, an OPC may beperformed on either the inner PCA 103 or the outer PCA 105 of theoptical disc 100, and information recording may be performed over thewhole surface of the optical disc 100 at the same liner velocity usingthe thus-determined optimum recording power.

A description will now be given, with reference to a flowchart shown inFIG. 6, of the OPC process in the controller 11 according to the presentembodiment. As shown in FIG. 6, first, a recorded state of theinformation recording area 104 of the recording layer (first layer) 101of the optical disc 100 is checked using the reproduction signal RF ormanagement information of the optical disc 100 (step S21). When usingthe reproduction signal RF, the optical pickup 5 is moved in a radialdirection from an inner side to an outer side so as to acquire thereproduction signal RF, and the position information of the opticalpickup 5 at this time and information regarding presence of thereproduction signal RF are stored. When using the management informationof the optical disc 100, information recorded on the managementinformation recording area (not shown) is reproduced and checks how farthe information is recorded. After checking the recorded state of theinformation recording area 104 of the recording layer (first layer) 101of the optical disc 100 as mentioned above, an OPC is performed so as toacquire an optimum recording power.

If information is recorded on the information record area 104 of therecording layer (first layer) 101 of the optical disc 100, (Y of stepS22: state determination means), an OPC is performed on the inner PCA103 (or the outer PCA 105) of the recording layer (first layer) 101 ofthe optical disc 100 (step S23: OPC means). Thereafter, an OPC isperformed on the inner PCA 103 (or the outer PCA 105) of the recordinglayer (second layer) 102 of the optical disc 100 (step S24: OPC means).

On the other hand, if information is not recorded on the informationrecording area 104 of the recording-layer (first layer) 101 of theoptical disc 100 (N of step S22: state determination means), an OPC isperformed on the inner PCA 103 (or the outer PCA 105) of the recordinglayer (second layer) 102 of the optical disc 100 (step S25: OPC means).Thereafter, an OPC is performed on the inner PCA 103 (or the outer PCA105) of the recording layer (first layer) 101 of the optical disc 100(step S26: OPC means).

The reason for first performing the OPC on the recording layer (firstlayer) 101 of the optical disc 100, when information is recorded on theinformation recording area 104 of the recording layer (first layer) 101of the optical disc 100, is as follows. That is, if information isrecorded on the information recording area 104 of the recording layer(first layer) 101 of the optical disc 100, an OPC is performed on theinner PCA 103 (or the outer PCA 105) of the recording layer (secondlayer) 102 of the optical disc 100 in a state where information iswritten in the inner PCA 103 (or the outer PCA 105) of the recordinglayer (first layer) 101 of the optical disc 100 since the OPC is firstperformed on the recording layer (first layer) 101 of the optical disc100. Thus, an optimum recording power is acquired in the same statewhere information is recorded on the information recording area 104 ofthe recording layer (first layer) 101 of the optical disc 100.Similarly, if information is not recorded on the information recordingarea 104 of the recording layer (first layer) 101 of the optical disc100, the OPC is first performed on the recording layer (second layer)102 of the optical disc 100 so that an optimum recording power isacquired in the same state where information is not recorded on theinformation recording area 104 of the recording layer (first layer) 101of the optical disc 100. As mentioned above, an optimum recording powercan be acquired in the same state where information is recorded on therecording area.

After the OPC on the inner PCA 103 (or the outer PCA 105) of the opticaldisc 100 is completed as mentioned above, the thus-acquired optimumrecording power is set as the optimum recording power of the opticaldisc 100 (step S27), and information recording is started (step S28).

Here, when performing information recording according to the constantlinear velocity using the optical disc 100 having a recording layer of amultilayer structure, an optimum recording power can be obtained underthe same condition as that when performing an information recordingoperation. Thereby, a stable recording quality can be maintained whenperforming information recording according to the constant linearvelocity using the optical disc 100 having a recording layer of amultilayer structure.

It should be noted that since a rotation speed must be increased as arecording point goes further inner side when the CLV method is used, itmay become difficult to rotate the optical disc at such a high speed.Thus, a motor cost may be increased so as to provided a spindle motorthat can achieve a higher rotation speed, and an increase in therotation speed may increase noise and vibration. Additionally, it maybecome difficult to design the servo system. Thus, instead of limitingan increase in the rotation speed on the inner side, measures may betaken to limit a decrease in the rotation speed on the outer side. Thatis, in such a case, the linear velocity increases toward the outer side.Therefore, as explained in the first embodiment, a result of an OPC atthe outer side and a result of an OPC at the inner side are acquired soas to set a recording power at an intermediate linear velocity as anoptimum recording power of the optical disc 100.

A description will now be given, with reference to FIG. 7, of a thirdembodiment of the present invention. In the third embodiment, thepresent invention is applied to a desk-top type personal computer 50,which is equipped with the optical disc drive apparatus 1 such asexplained in the above-mentioned embodiments in addition to a 3.5-inchflexible disc drive apparatus 51. The optical disc drive apparatus 1 maybe integrally incorporated in the personal computer 50, or may be abuilt-in type. Accordingly, a host is also incorporated in the personalcomputer 50.

Since the above-mentioned optical disk drive apparatus 1 is built in thepersonal computer 50, the optical disk drive apparatus 1, which canacquire an optimum recording power in an OPC operation during ainformation recording operation according to the constant linearvelocity method or the constant angular velocity method using themultilayer optical disc 100 having the two-layer recording layer, can beused as a memory apparatus of the personal computer 50.

It should be noted that the optical disc drive apparatus is not limitedto be built in the personal computer 50 as in the present embodiment,and may be provided alone and connected to an information processingapparatus such as an external host apparatus. Moreover, the personalcomputer 50 is not limited to the desk-top type, and a portable typepersonal computer such as a notebook type computer may be used.

Additionally, a program that describes the above-mentioned opticalinformation recording method may be stored in a processor readablemedium such as a CD-R or a flexible disc so that the personal computer50 can perform the function according to the information recordingmethod by loading the processor readable medium to the personal computer50 as shown in FIG. 7.

The present invention is not limited to the specifically disclosedembodiments, and variations and modifications may be made withoutdeparting from the scope of the present invention.

The present application is based on PCT application JP2004/003938, filedMar. 23, 2004 and Japanese priority applications No. 2003-080826 filedMar. 24, 2003 and No. 2004-026683 filed Feb. 3, 2004, the entirecontents of which are hereby incorporated by reference.

1. An optical information recording method for recording information onan optical information recording medium of a rotating type, which has aplurality of recording layers each having an information recording areain which information is recorded using a laser beam according to aconstant angular velocity method, said optical information recordingmethod comprising: performing an optimum power control (OPC) on a firstlayer, subsequently on a second layer, so as to acquire a first optimumrecording power; performing an OPC on the second layer, subsequently onthe first layer, so as to acquire a second optimum recording power; andstoring the acquired first and second optimum recording powers in anon-volatile memory, wherein the step of performing an OPC on a secondlayer, subsequently on a first layer, comprises: performing an OPC on anouter PCA of the second layer; and performing an OPC on an outer PCA ofthe first layer.
 2. An optical information recording apparatus forrecording information on an optical information recording medium of arotating type, which has a plurality of recording layers each having aninformation recording area in which information is recorded using alaser beam according to a constant angular velocity method, said opticalinformation recording apparatus comprising: a first optimum recordingpower obtaining circuit for performing an optimum power control (OPC) ona first layer, subsequently on a second layer, so as to acquire a firstoptimum recording power; a second optimum recording power obtainingcircuit for performing an OPC on the second layer, subsequently on thefirst layer, so as to acquire a second optimum recording power; and anon-volatile memory for storing the acquired first and second optimumrecording powers, wherein the performing an OPC on a second layer,subsequently on a first layer, comprises: performing an OPC on an outerPCA of the second layer; and performing an OPC on an outer PCA of thefirst layer.
 3. An information processing apparatus for processing aplurality of kinds of information processing, comprising: an optimumpower control (OPC) circuit for performing an OPC on a first layer,subsequently on a second layer, so as to acquire a first optimumrecording power; a second optimum recording power obtaining circuit forperforming an OPC on the second layer, subsequently on the first layer,so as to acquire a second optimum recording power; and a non-volatilememory for storing the acquired first and second optimum recordingpowers, wherein the performing an OPC on a second layer, subsequently ona first layer, comprises: performing an OPC on an outer PCA of thesecond layer; and performing an OPC on an outer PCA of the first layer.4. A computer-readable medium storing a program to be installed in acomputer of an information recording apparatus for recording informationon an optical information recording medium of a rotating type, which hasa plurality of recording layers each having an information recordingarea in which information is recorded using a laser beam according to aconstant angular velocity method, said program causing said computer toperform functions of: performing an optimum power control (OPC) on afirst layer, subsequently on a second layer, so as to acquire a firstoptimum recording power; performing an OPC on the second layer,subsequently on the first layer, so as to acquire a second optimumrecording power; and storing the acquired first and second optimumrecording powers in a non-volatile memory, wherein the performing an OPCon a second layer, subsequently on a first layer, comprises: performingan OPC on an outer PCA of the second layer; and performing an OPC on anouter PCA of the first layer.